The proposed research will be a continuation of studies begun in 1972 on the distraction effect of material rewards in children's discrimination learning. As it now appears to us that distraction in discrimination learning is but one outcropping from a broad and pervasive detrimental effect which tangible reward can have on performance, the proposed studies will appropriately range over a variety of tasks (probability, learning, incidental learning, and Einstellung problems). Along with these soundings for evidence of harmful effects of reward in varied settings, we will attempt to isolate some of the subject and reinforcement variables that determine the detrimental effects of reward and whether the detrimental effects extend beyond performance factors to attitudes. All of these goals will be furthered by a systematic review of the literature in which we expect to find relevant studies heretofore overlooked because of the virtually unchallenged assumption that reward can only be beneficial.